mqueue.c revision 1638113d9d8b7e04c1eeae9014d43f6381a74040
1/* 2 * POSIX message queues filesystem for Linux. 3 * 4 * Copyright (C) 2003,2004 Krzysztof Benedyczak (golbi@mat.uni.torun.pl) 5 * Michal Wronski (michal.wronski@gmail.com) 6 * 7 * Spinlocks: Mohamed Abbas (abbas.mohamed@intel.com) 8 * Lockless receive & send, fd based notify: 9 * Manfred Spraul (manfred@colorfullife.com) 10 * 11 * Audit: George Wilson (ltcgcw@us.ibm.com) 12 * 13 * This file is released under the GPL. 14 */ 15 16#include <linux/capability.h> 17#include <linux/init.h> 18#include <linux/pagemap.h> 19#include <linux/file.h> 20#include <linux/mount.h> 21#include <linux/namei.h> 22#include <linux/sysctl.h> 23#include <linux/poll.h> 24#include <linux/mqueue.h> 25#include <linux/msg.h> 26#include <linux/skbuff.h> 27#include <linux/vmalloc.h> 28#include <linux/netlink.h> 29#include <linux/syscalls.h> 30#include <linux/audit.h> 31#include <linux/signal.h> 32#include <linux/mutex.h> 33#include <linux/nsproxy.h> 34#include <linux/pid.h> 35#include <linux/ipc_namespace.h> 36#include <linux/user_namespace.h> 37#include <linux/slab.h> 38 39#include <net/sock.h> 40#include "util.h" 41 42#define MQUEUE_MAGIC 0x19800202 43#define DIRENT_SIZE 20 44#define FILENT_SIZE 80 45 46#define SEND 0 47#define RECV 1 48 49#define STATE_NONE 0 50#define STATE_PENDING 1 51#define STATE_READY 2 52 53struct posix_msg_tree_node { 54 struct rb_node rb_node; 55 struct list_head msg_list; 56 int priority; 57}; 58 59struct ext_wait_queue { /* queue of sleeping tasks */ 60 struct task_struct *task; 61 struct list_head list; 62 struct msg_msg *msg; /* ptr of loaded message */ 63 int state; /* one of STATE_* values */ 64}; 65 66struct mqueue_inode_info { 67 spinlock_t lock; 68 struct inode vfs_inode; 69 wait_queue_head_t wait_q; 70 71 struct rb_root msg_tree; 72 struct posix_msg_tree_node *node_cache; 73 struct mq_attr attr; 74 75 struct sigevent notify; 76 struct pid* notify_owner; 77 struct user_namespace *notify_user_ns; 78 struct user_struct *user; /* user who created, for accounting */ 79 struct sock *notify_sock; 80 struct sk_buff *notify_cookie; 81 82 /* for tasks waiting for free space and messages, respectively */ 83 struct ext_wait_queue e_wait_q[2]; 84 85 unsigned long qsize; /* size of queue in memory (sum of all msgs) */ 86}; 87 88static const struct inode_operations mqueue_dir_inode_operations; 89static const struct file_operations mqueue_file_operations; 90static const struct super_operations mqueue_super_ops; 91static void remove_notification(struct mqueue_inode_info *info); 92 93static struct kmem_cache *mqueue_inode_cachep; 94 95static struct ctl_table_header * mq_sysctl_table; 96 97static inline struct mqueue_inode_info *MQUEUE_I(struct inode *inode) 98{ 99 return container_of(inode, struct mqueue_inode_info, vfs_inode); 100} 101 102/* 103 * This routine should be called with the mq_lock held. 104 */ 105static inline struct ipc_namespace *__get_ns_from_inode(struct inode *inode) 106{ 107 return get_ipc_ns(inode->i_sb->s_fs_info); 108} 109 110static struct ipc_namespace *get_ns_from_inode(struct inode *inode) 111{ 112 struct ipc_namespace *ns; 113 114 spin_lock(&mq_lock); 115 ns = __get_ns_from_inode(inode); 116 spin_unlock(&mq_lock); 117 return ns; 118} 119 120/* Auxiliary functions to manipulate messages' list */ 121static int msg_insert(struct msg_msg *msg, struct mqueue_inode_info *info) 122{ 123 struct rb_node **p, *parent = NULL; 124 struct posix_msg_tree_node *leaf; 125 126 p = &info->msg_tree.rb_node; 127 while (*p) { 128 parent = *p; 129 leaf = rb_entry(parent, struct posix_msg_tree_node, rb_node); 130 131 if (likely(leaf->priority == msg->m_type)) 132 goto insert_msg; 133 else if (msg->m_type < leaf->priority) 134 p = &(*p)->rb_left; 135 else 136 p = &(*p)->rb_right; 137 } 138 if (info->node_cache) { 139 leaf = info->node_cache; 140 info->node_cache = NULL; 141 } else { 142 leaf = kmalloc(sizeof(*leaf), GFP_ATOMIC); 143 if (!leaf) 144 return -ENOMEM; 145 INIT_LIST_HEAD(&leaf->msg_list); 146 info->qsize += sizeof(*leaf); 147 } 148 leaf->priority = msg->m_type; 149 rb_link_node(&leaf->rb_node, parent, p); 150 rb_insert_color(&leaf->rb_node, &info->msg_tree); 151insert_msg: 152 info->attr.mq_curmsgs++; 153 info->qsize += msg->m_ts; 154 list_add_tail(&msg->m_list, &leaf->msg_list); 155 return 0; 156} 157 158static inline struct msg_msg *msg_get(struct mqueue_inode_info *info) 159{ 160 struct rb_node **p, *parent = NULL; 161 struct posix_msg_tree_node *leaf; 162 struct msg_msg *msg; 163 164try_again: 165 p = &info->msg_tree.rb_node; 166 while (*p) { 167 parent = *p; 168 /* 169 * During insert, low priorities go to the left and high to the 170 * right. On receive, we want the highest priorities first, so 171 * walk all the way to the right. 172 */ 173 p = &(*p)->rb_right; 174 } 175 if (!parent) { 176 if (info->attr.mq_curmsgs) { 177 pr_warn_once("Inconsistency in POSIX message queue, " 178 "no tree element, but supposedly messages " 179 "should exist!\n"); 180 info->attr.mq_curmsgs = 0; 181 } 182 return NULL; 183 } 184 leaf = rb_entry(parent, struct posix_msg_tree_node, rb_node); 185 if (unlikely(list_empty(&leaf->msg_list))) { 186 pr_warn_once("Inconsistency in POSIX message queue, " 187 "empty leaf node but we haven't implemented " 188 "lazy leaf delete!\n"); 189 rb_erase(&leaf->rb_node, &info->msg_tree); 190 if (info->node_cache) { 191 info->qsize -= sizeof(*leaf); 192 kfree(leaf); 193 } else { 194 info->node_cache = leaf; 195 } 196 goto try_again; 197 } else { 198 msg = list_first_entry(&leaf->msg_list, 199 struct msg_msg, m_list); 200 list_del(&msg->m_list); 201 if (list_empty(&leaf->msg_list)) { 202 rb_erase(&leaf->rb_node, &info->msg_tree); 203 if (info->node_cache) { 204 info->qsize -= sizeof(*leaf); 205 kfree(leaf); 206 } else { 207 info->node_cache = leaf; 208 } 209 } 210 } 211 info->attr.mq_curmsgs--; 212 info->qsize -= msg->m_ts; 213 return msg; 214} 215 216static struct inode *mqueue_get_inode(struct super_block *sb, 217 struct ipc_namespace *ipc_ns, umode_t mode, 218 struct mq_attr *attr) 219{ 220 struct user_struct *u = current_user(); 221 struct inode *inode; 222 int ret = -ENOMEM; 223 224 inode = new_inode(sb); 225 if (!inode) 226 goto err; 227 228 inode->i_ino = get_next_ino(); 229 inode->i_mode = mode; 230 inode->i_uid = current_fsuid(); 231 inode->i_gid = current_fsgid(); 232 inode->i_mtime = inode->i_ctime = inode->i_atime = CURRENT_TIME; 233 234 if (S_ISREG(mode)) { 235 struct mqueue_inode_info *info; 236 unsigned long mq_bytes, mq_treesize; 237 238 inode->i_fop = &mqueue_file_operations; 239 inode->i_size = FILENT_SIZE; 240 /* mqueue specific info */ 241 info = MQUEUE_I(inode); 242 spin_lock_init(&info->lock); 243 init_waitqueue_head(&info->wait_q); 244 INIT_LIST_HEAD(&info->e_wait_q[0].list); 245 INIT_LIST_HEAD(&info->e_wait_q[1].list); 246 info->notify_owner = NULL; 247 info->notify_user_ns = NULL; 248 info->qsize = 0; 249 info->user = NULL; /* set when all is ok */ 250 info->msg_tree = RB_ROOT; 251 info->node_cache = NULL; 252 memset(&info->attr, 0, sizeof(info->attr)); 253 info->attr.mq_maxmsg = min(ipc_ns->mq_msg_max, 254 ipc_ns->mq_msg_default); 255 info->attr.mq_msgsize = min(ipc_ns->mq_msgsize_max, 256 ipc_ns->mq_msgsize_default); 257 if (attr) { 258 info->attr.mq_maxmsg = attr->mq_maxmsg; 259 info->attr.mq_msgsize = attr->mq_msgsize; 260 } 261 /* 262 * We used to allocate a static array of pointers and account 263 * the size of that array as well as one msg_msg struct per 264 * possible message into the queue size. That's no longer 265 * accurate as the queue is now an rbtree and will grow and 266 * shrink depending on usage patterns. We can, however, still 267 * account one msg_msg struct per message, but the nodes are 268 * allocated depending on priority usage, and most programs 269 * only use one, or a handful, of priorities. However, since 270 * this is pinned memory, we need to assume worst case, so 271 * that means the min(mq_maxmsg, max_priorities) * struct 272 * posix_msg_tree_node. 273 */ 274 mq_treesize = info->attr.mq_maxmsg * sizeof(struct msg_msg) + 275 min_t(unsigned int, info->attr.mq_maxmsg, MQ_PRIO_MAX) * 276 sizeof(struct posix_msg_tree_node); 277 278 mq_bytes = mq_treesize + (info->attr.mq_maxmsg * 279 info->attr.mq_msgsize); 280 281 spin_lock(&mq_lock); 282 if (u->mq_bytes + mq_bytes < u->mq_bytes || 283 u->mq_bytes + mq_bytes > rlimit(RLIMIT_MSGQUEUE)) { 284 spin_unlock(&mq_lock); 285 /* mqueue_evict_inode() releases info->messages */ 286 ret = -EMFILE; 287 goto out_inode; 288 } 289 u->mq_bytes += mq_bytes; 290 spin_unlock(&mq_lock); 291 292 /* all is ok */ 293 info->user = get_uid(u); 294 } else if (S_ISDIR(mode)) { 295 inc_nlink(inode); 296 /* Some things misbehave if size == 0 on a directory */ 297 inode->i_size = 2 * DIRENT_SIZE; 298 inode->i_op = &mqueue_dir_inode_operations; 299 inode->i_fop = &simple_dir_operations; 300 } 301 302 return inode; 303out_inode: 304 iput(inode); 305err: 306 return ERR_PTR(ret); 307} 308 309static int mqueue_fill_super(struct super_block *sb, void *data, int silent) 310{ 311 struct inode *inode; 312 struct ipc_namespace *ns = data; 313 314 sb->s_blocksize = PAGE_CACHE_SIZE; 315 sb->s_blocksize_bits = PAGE_CACHE_SHIFT; 316 sb->s_magic = MQUEUE_MAGIC; 317 sb->s_op = &mqueue_super_ops; 318 319 inode = mqueue_get_inode(sb, ns, S_IFDIR | S_ISVTX | S_IRWXUGO, NULL); 320 if (IS_ERR(inode)) 321 return PTR_ERR(inode); 322 323 sb->s_root = d_make_root(inode); 324 if (!sb->s_root) 325 return -ENOMEM; 326 return 0; 327} 328 329static struct dentry *mqueue_mount(struct file_system_type *fs_type, 330 int flags, const char *dev_name, 331 void *data) 332{ 333 if (!(flags & MS_KERNMOUNT)) 334 data = current->nsproxy->ipc_ns; 335 return mount_ns(fs_type, flags, data, mqueue_fill_super); 336} 337 338static void init_once(void *foo) 339{ 340 struct mqueue_inode_info *p = (struct mqueue_inode_info *) foo; 341 342 inode_init_once(&p->vfs_inode); 343} 344 345static struct inode *mqueue_alloc_inode(struct super_block *sb) 346{ 347 struct mqueue_inode_info *ei; 348 349 ei = kmem_cache_alloc(mqueue_inode_cachep, GFP_KERNEL); 350 if (!ei) 351 return NULL; 352 return &ei->vfs_inode; 353} 354 355static void mqueue_i_callback(struct rcu_head *head) 356{ 357 struct inode *inode = container_of(head, struct inode, i_rcu); 358 kmem_cache_free(mqueue_inode_cachep, MQUEUE_I(inode)); 359} 360 361static void mqueue_destroy_inode(struct inode *inode) 362{ 363 call_rcu(&inode->i_rcu, mqueue_i_callback); 364} 365 366static void mqueue_evict_inode(struct inode *inode) 367{ 368 struct mqueue_inode_info *info; 369 struct user_struct *user; 370 unsigned long mq_bytes, mq_treesize; 371 struct ipc_namespace *ipc_ns; 372 struct msg_msg *msg; 373 374 clear_inode(inode); 375 376 if (S_ISDIR(inode->i_mode)) 377 return; 378 379 ipc_ns = get_ns_from_inode(inode); 380 info = MQUEUE_I(inode); 381 spin_lock(&info->lock); 382 while ((msg = msg_get(info)) != NULL) 383 free_msg(msg); 384 kfree(info->node_cache); 385 spin_unlock(&info->lock); 386 387 /* Total amount of bytes accounted for the mqueue */ 388 mq_treesize = info->attr.mq_maxmsg * sizeof(struct msg_msg) + 389 min_t(unsigned int, info->attr.mq_maxmsg, MQ_PRIO_MAX) * 390 sizeof(struct posix_msg_tree_node); 391 392 mq_bytes = mq_treesize + (info->attr.mq_maxmsg * 393 info->attr.mq_msgsize); 394 395 user = info->user; 396 if (user) { 397 spin_lock(&mq_lock); 398 user->mq_bytes -= mq_bytes; 399 /* 400 * get_ns_from_inode() ensures that the 401 * (ipc_ns = sb->s_fs_info) is either a valid ipc_ns 402 * to which we now hold a reference, or it is NULL. 403 * We can't put it here under mq_lock, though. 404 */ 405 if (ipc_ns) 406 ipc_ns->mq_queues_count--; 407 spin_unlock(&mq_lock); 408 free_uid(user); 409 } 410 if (ipc_ns) 411 put_ipc_ns(ipc_ns); 412} 413 414static int mqueue_create(struct inode *dir, struct dentry *dentry, 415 umode_t mode, bool excl) 416{ 417 struct inode *inode; 418 struct mq_attr *attr = dentry->d_fsdata; 419 int error; 420 struct ipc_namespace *ipc_ns; 421 422 spin_lock(&mq_lock); 423 ipc_ns = __get_ns_from_inode(dir); 424 if (!ipc_ns) { 425 error = -EACCES; 426 goto out_unlock; 427 } 428 if (ipc_ns->mq_queues_count >= HARD_QUEUESMAX || 429 (ipc_ns->mq_queues_count >= ipc_ns->mq_queues_max && 430 !capable(CAP_SYS_RESOURCE))) { 431 error = -ENOSPC; 432 goto out_unlock; 433 } 434 ipc_ns->mq_queues_count++; 435 spin_unlock(&mq_lock); 436 437 inode = mqueue_get_inode(dir->i_sb, ipc_ns, mode, attr); 438 if (IS_ERR(inode)) { 439 error = PTR_ERR(inode); 440 spin_lock(&mq_lock); 441 ipc_ns->mq_queues_count--; 442 goto out_unlock; 443 } 444 445 put_ipc_ns(ipc_ns); 446 dir->i_size += DIRENT_SIZE; 447 dir->i_ctime = dir->i_mtime = dir->i_atime = CURRENT_TIME; 448 449 d_instantiate(dentry, inode); 450 dget(dentry); 451 return 0; 452out_unlock: 453 spin_unlock(&mq_lock); 454 if (ipc_ns) 455 put_ipc_ns(ipc_ns); 456 return error; 457} 458 459static int mqueue_unlink(struct inode *dir, struct dentry *dentry) 460{ 461 struct inode *inode = dentry->d_inode; 462 463 dir->i_ctime = dir->i_mtime = dir->i_atime = CURRENT_TIME; 464 dir->i_size -= DIRENT_SIZE; 465 drop_nlink(inode); 466 dput(dentry); 467 return 0; 468} 469 470/* 471* This is routine for system read from queue file. 472* To avoid mess with doing here some sort of mq_receive we allow 473* to read only queue size & notification info (the only values 474* that are interesting from user point of view and aren't accessible 475* through std routines) 476*/ 477static ssize_t mqueue_read_file(struct file *filp, char __user *u_data, 478 size_t count, loff_t *off) 479{ 480 struct mqueue_inode_info *info = MQUEUE_I(filp->f_path.dentry->d_inode); 481 char buffer[FILENT_SIZE]; 482 ssize_t ret; 483 484 spin_lock(&info->lock); 485 snprintf(buffer, sizeof(buffer), 486 "QSIZE:%-10lu NOTIFY:%-5d SIGNO:%-5d NOTIFY_PID:%-6d\n", 487 info->qsize, 488 info->notify_owner ? info->notify.sigev_notify : 0, 489 (info->notify_owner && 490 info->notify.sigev_notify == SIGEV_SIGNAL) ? 491 info->notify.sigev_signo : 0, 492 pid_vnr(info->notify_owner)); 493 spin_unlock(&info->lock); 494 buffer[sizeof(buffer)-1] = '\0'; 495 496 ret = simple_read_from_buffer(u_data, count, off, buffer, 497 strlen(buffer)); 498 if (ret <= 0) 499 return ret; 500 501 filp->f_path.dentry->d_inode->i_atime = filp->f_path.dentry->d_inode->i_ctime = CURRENT_TIME; 502 return ret; 503} 504 505static int mqueue_flush_file(struct file *filp, fl_owner_t id) 506{ 507 struct mqueue_inode_info *info = MQUEUE_I(filp->f_path.dentry->d_inode); 508 509 spin_lock(&info->lock); 510 if (task_tgid(current) == info->notify_owner) 511 remove_notification(info); 512 513 spin_unlock(&info->lock); 514 return 0; 515} 516 517static unsigned int mqueue_poll_file(struct file *filp, struct poll_table_struct *poll_tab) 518{ 519 struct mqueue_inode_info *info = MQUEUE_I(filp->f_path.dentry->d_inode); 520 int retval = 0; 521 522 poll_wait(filp, &info->wait_q, poll_tab); 523 524 spin_lock(&info->lock); 525 if (info->attr.mq_curmsgs) 526 retval = POLLIN | POLLRDNORM; 527 528 if (info->attr.mq_curmsgs < info->attr.mq_maxmsg) 529 retval |= POLLOUT | POLLWRNORM; 530 spin_unlock(&info->lock); 531 532 return retval; 533} 534 535/* Adds current to info->e_wait_q[sr] before element with smaller prio */ 536static void wq_add(struct mqueue_inode_info *info, int sr, 537 struct ext_wait_queue *ewp) 538{ 539 struct ext_wait_queue *walk; 540 541 ewp->task = current; 542 543 list_for_each_entry(walk, &info->e_wait_q[sr].list, list) { 544 if (walk->task->static_prio <= current->static_prio) { 545 list_add_tail(&ewp->list, &walk->list); 546 return; 547 } 548 } 549 list_add_tail(&ewp->list, &info->e_wait_q[sr].list); 550} 551 552/* 553 * Puts current task to sleep. Caller must hold queue lock. After return 554 * lock isn't held. 555 * sr: SEND or RECV 556 */ 557static int wq_sleep(struct mqueue_inode_info *info, int sr, 558 ktime_t *timeout, struct ext_wait_queue *ewp) 559{ 560 int retval; 561 signed long time; 562 563 wq_add(info, sr, ewp); 564 565 for (;;) { 566 set_current_state(TASK_INTERRUPTIBLE); 567 568 spin_unlock(&info->lock); 569 time = schedule_hrtimeout_range_clock(timeout, 0, 570 HRTIMER_MODE_ABS, CLOCK_REALTIME); 571 572 while (ewp->state == STATE_PENDING) 573 cpu_relax(); 574 575 if (ewp->state == STATE_READY) { 576 retval = 0; 577 goto out; 578 } 579 spin_lock(&info->lock); 580 if (ewp->state == STATE_READY) { 581 retval = 0; 582 goto out_unlock; 583 } 584 if (signal_pending(current)) { 585 retval = -ERESTARTSYS; 586 break; 587 } 588 if (time == 0) { 589 retval = -ETIMEDOUT; 590 break; 591 } 592 } 593 list_del(&ewp->list); 594out_unlock: 595 spin_unlock(&info->lock); 596out: 597 return retval; 598} 599 600/* 601 * Returns waiting task that should be serviced first or NULL if none exists 602 */ 603static struct ext_wait_queue *wq_get_first_waiter( 604 struct mqueue_inode_info *info, int sr) 605{ 606 struct list_head *ptr; 607 608 ptr = info->e_wait_q[sr].list.prev; 609 if (ptr == &info->e_wait_q[sr].list) 610 return NULL; 611 return list_entry(ptr, struct ext_wait_queue, list); 612} 613 614 615static inline void set_cookie(struct sk_buff *skb, char code) 616{ 617 ((char*)skb->data)[NOTIFY_COOKIE_LEN-1] = code; 618} 619 620/* 621 * The next function is only to split too long sys_mq_timedsend 622 */ 623static void __do_notify(struct mqueue_inode_info *info) 624{ 625 /* notification 626 * invoked when there is registered process and there isn't process 627 * waiting synchronously for message AND state of queue changed from 628 * empty to not empty. Here we are sure that no one is waiting 629 * synchronously. */ 630 if (info->notify_owner && 631 info->attr.mq_curmsgs == 1) { 632 struct siginfo sig_i; 633 switch (info->notify.sigev_notify) { 634 case SIGEV_NONE: 635 break; 636 case SIGEV_SIGNAL: 637 /* sends signal */ 638 639 sig_i.si_signo = info->notify.sigev_signo; 640 sig_i.si_errno = 0; 641 sig_i.si_code = SI_MESGQ; 642 sig_i.si_value = info->notify.sigev_value; 643 /* map current pid/uid into info->owner's namespaces */ 644 rcu_read_lock(); 645 sig_i.si_pid = task_tgid_nr_ns(current, 646 ns_of_pid(info->notify_owner)); 647 sig_i.si_uid = from_kuid_munged(info->notify_user_ns, current_uid()); 648 rcu_read_unlock(); 649 650 kill_pid_info(info->notify.sigev_signo, 651 &sig_i, info->notify_owner); 652 break; 653 case SIGEV_THREAD: 654 set_cookie(info->notify_cookie, NOTIFY_WOKENUP); 655 netlink_sendskb(info->notify_sock, info->notify_cookie); 656 break; 657 } 658 /* after notification unregisters process */ 659 put_pid(info->notify_owner); 660 put_user_ns(info->notify_user_ns); 661 info->notify_owner = NULL; 662 info->notify_user_ns = NULL; 663 } 664 wake_up(&info->wait_q); 665} 666 667static int prepare_timeout(const struct timespec __user *u_abs_timeout, 668 ktime_t *expires, struct timespec *ts) 669{ 670 if (copy_from_user(ts, u_abs_timeout, sizeof(struct timespec))) 671 return -EFAULT; 672 if (!timespec_valid(ts)) 673 return -EINVAL; 674 675 *expires = timespec_to_ktime(*ts); 676 return 0; 677} 678 679static void remove_notification(struct mqueue_inode_info *info) 680{ 681 if (info->notify_owner != NULL && 682 info->notify.sigev_notify == SIGEV_THREAD) { 683 set_cookie(info->notify_cookie, NOTIFY_REMOVED); 684 netlink_sendskb(info->notify_sock, info->notify_cookie); 685 } 686 put_pid(info->notify_owner); 687 put_user_ns(info->notify_user_ns); 688 info->notify_owner = NULL; 689 info->notify_user_ns = NULL; 690} 691 692static int mq_attr_ok(struct ipc_namespace *ipc_ns, struct mq_attr *attr) 693{ 694 int mq_treesize; 695 unsigned long total_size; 696 697 if (attr->mq_maxmsg <= 0 || attr->mq_msgsize <= 0) 698 return -EINVAL; 699 if (capable(CAP_SYS_RESOURCE)) { 700 if (attr->mq_maxmsg > HARD_MSGMAX || 701 attr->mq_msgsize > HARD_MSGSIZEMAX) 702 return -EINVAL; 703 } else { 704 if (attr->mq_maxmsg > ipc_ns->mq_msg_max || 705 attr->mq_msgsize > ipc_ns->mq_msgsize_max) 706 return -EINVAL; 707 } 708 /* check for overflow */ 709 if (attr->mq_msgsize > ULONG_MAX/attr->mq_maxmsg) 710 return -EOVERFLOW; 711 mq_treesize = attr->mq_maxmsg * sizeof(struct msg_msg) + 712 min_t(unsigned int, attr->mq_maxmsg, MQ_PRIO_MAX) * 713 sizeof(struct posix_msg_tree_node); 714 total_size = attr->mq_maxmsg * attr->mq_msgsize; 715 if (total_size + mq_treesize < total_size) 716 return -EOVERFLOW; 717 return 0; 718} 719 720/* 721 * Invoked when creating a new queue via sys_mq_open 722 */ 723static struct file *do_create(struct ipc_namespace *ipc_ns, struct inode *dir, 724 struct path *path, int oflag, umode_t mode, 725 struct mq_attr *attr) 726{ 727 const struct cred *cred = current_cred(); 728 int ret; 729 730 if (attr) { 731 ret = mq_attr_ok(ipc_ns, attr); 732 if (ret) 733 return ERR_PTR(ret); 734 /* store for use during create */ 735 path->dentry->d_fsdata = attr; 736 } else { 737 struct mq_attr def_attr; 738 739 def_attr.mq_maxmsg = min(ipc_ns->mq_msg_max, 740 ipc_ns->mq_msg_default); 741 def_attr.mq_msgsize = min(ipc_ns->mq_msgsize_max, 742 ipc_ns->mq_msgsize_default); 743 ret = mq_attr_ok(ipc_ns, &def_attr); 744 if (ret) 745 return ERR_PTR(ret); 746 } 747 748 mode &= ~current_umask(); 749 ret = vfs_create(dir, path->dentry, mode, true); 750 path->dentry->d_fsdata = NULL; 751 if (ret) 752 return ERR_PTR(ret); 753 return dentry_open(path, oflag, cred); 754} 755 756/* Opens existing queue */ 757static struct file *do_open(struct path *path, int oflag) 758{ 759 static const int oflag2acc[O_ACCMODE] = { MAY_READ, MAY_WRITE, 760 MAY_READ | MAY_WRITE }; 761 int acc; 762 if ((oflag & O_ACCMODE) == (O_RDWR | O_WRONLY)) 763 return ERR_PTR(-EINVAL); 764 acc = oflag2acc[oflag & O_ACCMODE]; 765 if (inode_permission(path->dentry->d_inode, acc)) 766 return ERR_PTR(-EACCES); 767 return dentry_open(path, oflag, current_cred()); 768} 769 770SYSCALL_DEFINE4(mq_open, const char __user *, u_name, int, oflag, umode_t, mode, 771 struct mq_attr __user *, u_attr) 772{ 773 struct path path; 774 struct file *filp; 775 char *name; 776 struct mq_attr attr; 777 int fd, error; 778 struct ipc_namespace *ipc_ns = current->nsproxy->ipc_ns; 779 struct vfsmount *mnt = ipc_ns->mq_mnt; 780 struct dentry *root = mnt->mnt_root; 781 int ro; 782 783 if (u_attr && copy_from_user(&attr, u_attr, sizeof(struct mq_attr))) 784 return -EFAULT; 785 786 audit_mq_open(oflag, mode, u_attr ? &attr : NULL); 787 788 if (IS_ERR(name = getname(u_name))) 789 return PTR_ERR(name); 790 791 fd = get_unused_fd_flags(O_CLOEXEC); 792 if (fd < 0) 793 goto out_putname; 794 795 ro = mnt_want_write(mnt); /* we'll drop it in any case */ 796 error = 0; 797 mutex_lock(&root->d_inode->i_mutex); 798 path.dentry = lookup_one_len(name, root, strlen(name)); 799 if (IS_ERR(path.dentry)) { 800 error = PTR_ERR(path.dentry); 801 goto out_putfd; 802 } 803 path.mnt = mntget(mnt); 804 805 if (oflag & O_CREAT) { 806 if (path.dentry->d_inode) { /* entry already exists */ 807 audit_inode(name, path.dentry); 808 if (oflag & O_EXCL) { 809 error = -EEXIST; 810 goto out; 811 } 812 filp = do_open(&path, oflag); 813 } else { 814 if (ro) { 815 error = ro; 816 goto out; 817 } 818 filp = do_create(ipc_ns, root->d_inode, 819 &path, oflag, mode, 820 u_attr ? &attr : NULL); 821 } 822 } else { 823 if (!path.dentry->d_inode) { 824 error = -ENOENT; 825 goto out; 826 } 827 audit_inode(name, path.dentry); 828 filp = do_open(&path, oflag); 829 } 830 831 if (!IS_ERR(filp)) 832 fd_install(fd, filp); 833 else 834 error = PTR_ERR(filp); 835out: 836 path_put(&path); 837out_putfd: 838 if (error) { 839 put_unused_fd(fd); 840 fd = error; 841 } 842 mutex_unlock(&root->d_inode->i_mutex); 843 mnt_drop_write(mnt); 844out_putname: 845 putname(name); 846 return fd; 847} 848 849SYSCALL_DEFINE1(mq_unlink, const char __user *, u_name) 850{ 851 int err; 852 char *name; 853 struct dentry *dentry; 854 struct inode *inode = NULL; 855 struct ipc_namespace *ipc_ns = current->nsproxy->ipc_ns; 856 struct vfsmount *mnt = ipc_ns->mq_mnt; 857 858 name = getname(u_name); 859 if (IS_ERR(name)) 860 return PTR_ERR(name); 861 862 err = mnt_want_write(mnt); 863 if (err) 864 goto out_name; 865 mutex_lock_nested(&mnt->mnt_root->d_inode->i_mutex, I_MUTEX_PARENT); 866 dentry = lookup_one_len(name, mnt->mnt_root, strlen(name)); 867 if (IS_ERR(dentry)) { 868 err = PTR_ERR(dentry); 869 goto out_unlock; 870 } 871 872 inode = dentry->d_inode; 873 if (!inode) { 874 err = -ENOENT; 875 } else { 876 ihold(inode); 877 err = vfs_unlink(dentry->d_parent->d_inode, dentry); 878 } 879 dput(dentry); 880 881out_unlock: 882 mutex_unlock(&mnt->mnt_root->d_inode->i_mutex); 883 if (inode) 884 iput(inode); 885 mnt_drop_write(mnt); 886out_name: 887 putname(name); 888 889 return err; 890} 891 892/* Pipelined send and receive functions. 893 * 894 * If a receiver finds no waiting message, then it registers itself in the 895 * list of waiting receivers. A sender checks that list before adding the new 896 * message into the message array. If there is a waiting receiver, then it 897 * bypasses the message array and directly hands the message over to the 898 * receiver. 899 * The receiver accepts the message and returns without grabbing the queue 900 * spinlock. Therefore an intermediate STATE_PENDING state and memory barriers 901 * are necessary. The same algorithm is used for sysv semaphores, see 902 * ipc/sem.c for more details. 903 * 904 * The same algorithm is used for senders. 905 */ 906 907/* pipelined_send() - send a message directly to the task waiting in 908 * sys_mq_timedreceive() (without inserting message into a queue). 909 */ 910static inline void pipelined_send(struct mqueue_inode_info *info, 911 struct msg_msg *message, 912 struct ext_wait_queue *receiver) 913{ 914 receiver->msg = message; 915 list_del(&receiver->list); 916 receiver->state = STATE_PENDING; 917 wake_up_process(receiver->task); 918 smp_wmb(); 919 receiver->state = STATE_READY; 920} 921 922/* pipelined_receive() - if there is task waiting in sys_mq_timedsend() 923 * gets its message and put to the queue (we have one free place for sure). */ 924static inline void pipelined_receive(struct mqueue_inode_info *info) 925{ 926 struct ext_wait_queue *sender = wq_get_first_waiter(info, SEND); 927 928 if (!sender) { 929 /* for poll */ 930 wake_up_interruptible(&info->wait_q); 931 return; 932 } 933 if (msg_insert(sender->msg, info)) 934 return; 935 list_del(&sender->list); 936 sender->state = STATE_PENDING; 937 wake_up_process(sender->task); 938 smp_wmb(); 939 sender->state = STATE_READY; 940} 941 942SYSCALL_DEFINE5(mq_timedsend, mqd_t, mqdes, const char __user *, u_msg_ptr, 943 size_t, msg_len, unsigned int, msg_prio, 944 const struct timespec __user *, u_abs_timeout) 945{ 946 struct fd f; 947 struct inode *inode; 948 struct ext_wait_queue wait; 949 struct ext_wait_queue *receiver; 950 struct msg_msg *msg_ptr; 951 struct mqueue_inode_info *info; 952 ktime_t expires, *timeout = NULL; 953 struct timespec ts; 954 struct posix_msg_tree_node *new_leaf = NULL; 955 int ret = 0; 956 957 if (u_abs_timeout) { 958 int res = prepare_timeout(u_abs_timeout, &expires, &ts); 959 if (res) 960 return res; 961 timeout = &expires; 962 } 963 964 if (unlikely(msg_prio >= (unsigned long) MQ_PRIO_MAX)) 965 return -EINVAL; 966 967 audit_mq_sendrecv(mqdes, msg_len, msg_prio, timeout ? &ts : NULL); 968 969 f = fdget(mqdes); 970 if (unlikely(!f.file)) { 971 ret = -EBADF; 972 goto out; 973 } 974 975 inode = f.file->f_path.dentry->d_inode; 976 if (unlikely(f.file->f_op != &mqueue_file_operations)) { 977 ret = -EBADF; 978 goto out_fput; 979 } 980 info = MQUEUE_I(inode); 981 audit_inode(NULL, f.file->f_path.dentry); 982 983 if (unlikely(!(f.file->f_mode & FMODE_WRITE))) { 984 ret = -EBADF; 985 goto out_fput; 986 } 987 988 if (unlikely(msg_len > info->attr.mq_msgsize)) { 989 ret = -EMSGSIZE; 990 goto out_fput; 991 } 992 993 /* First try to allocate memory, before doing anything with 994 * existing queues. */ 995 msg_ptr = load_msg(u_msg_ptr, msg_len); 996 if (IS_ERR(msg_ptr)) { 997 ret = PTR_ERR(msg_ptr); 998 goto out_fput; 999 } 1000 msg_ptr->m_ts = msg_len; 1001 msg_ptr->m_type = msg_prio; 1002 1003 /* 1004 * msg_insert really wants us to have a valid, spare node struct so 1005 * it doesn't have to kmalloc a GFP_ATOMIC allocation, but it will 1006 * fall back to that if necessary. 1007 */ 1008 if (!info->node_cache) 1009 new_leaf = kmalloc(sizeof(*new_leaf), GFP_KERNEL); 1010 1011 spin_lock(&info->lock); 1012 1013 if (!info->node_cache && new_leaf) { 1014 /* Save our speculative allocation into the cache */ 1015 INIT_LIST_HEAD(&new_leaf->msg_list); 1016 info->node_cache = new_leaf; 1017 info->qsize += sizeof(*new_leaf); 1018 new_leaf = NULL; 1019 } else { 1020 kfree(new_leaf); 1021 } 1022 1023 if (info->attr.mq_curmsgs == info->attr.mq_maxmsg) { 1024 if (f.file->f_flags & O_NONBLOCK) { 1025 ret = -EAGAIN; 1026 } else { 1027 wait.task = current; 1028 wait.msg = (void *) msg_ptr; 1029 wait.state = STATE_NONE; 1030 ret = wq_sleep(info, SEND, timeout, &wait); 1031 /* 1032 * wq_sleep must be called with info->lock held, and 1033 * returns with the lock released 1034 */ 1035 goto out_free; 1036 } 1037 } else { 1038 receiver = wq_get_first_waiter(info, RECV); 1039 if (receiver) { 1040 pipelined_send(info, msg_ptr, receiver); 1041 } else { 1042 /* adds message to the queue */ 1043 ret = msg_insert(msg_ptr, info); 1044 if (ret) 1045 goto out_unlock; 1046 __do_notify(info); 1047 } 1048 inode->i_atime = inode->i_mtime = inode->i_ctime = 1049 CURRENT_TIME; 1050 } 1051out_unlock: 1052 spin_unlock(&info->lock); 1053out_free: 1054 if (ret) 1055 free_msg(msg_ptr); 1056out_fput: 1057 fdput(f); 1058out: 1059 return ret; 1060} 1061 1062SYSCALL_DEFINE5(mq_timedreceive, mqd_t, mqdes, char __user *, u_msg_ptr, 1063 size_t, msg_len, unsigned int __user *, u_msg_prio, 1064 const struct timespec __user *, u_abs_timeout) 1065{ 1066 ssize_t ret; 1067 struct msg_msg *msg_ptr; 1068 struct fd f; 1069 struct inode *inode; 1070 struct mqueue_inode_info *info; 1071 struct ext_wait_queue wait; 1072 ktime_t expires, *timeout = NULL; 1073 struct timespec ts; 1074 struct posix_msg_tree_node *new_leaf = NULL; 1075 1076 if (u_abs_timeout) { 1077 int res = prepare_timeout(u_abs_timeout, &expires, &ts); 1078 if (res) 1079 return res; 1080 timeout = &expires; 1081 } 1082 1083 audit_mq_sendrecv(mqdes, msg_len, 0, timeout ? &ts : NULL); 1084 1085 f = fdget(mqdes); 1086 if (unlikely(!f.file)) { 1087 ret = -EBADF; 1088 goto out; 1089 } 1090 1091 inode = f.file->f_path.dentry->d_inode; 1092 if (unlikely(f.file->f_op != &mqueue_file_operations)) { 1093 ret = -EBADF; 1094 goto out_fput; 1095 } 1096 info = MQUEUE_I(inode); 1097 audit_inode(NULL, f.file->f_path.dentry); 1098 1099 if (unlikely(!(f.file->f_mode & FMODE_READ))) { 1100 ret = -EBADF; 1101 goto out_fput; 1102 } 1103 1104 /* checks if buffer is big enough */ 1105 if (unlikely(msg_len < info->attr.mq_msgsize)) { 1106 ret = -EMSGSIZE; 1107 goto out_fput; 1108 } 1109 1110 /* 1111 * msg_insert really wants us to have a valid, spare node struct so 1112 * it doesn't have to kmalloc a GFP_ATOMIC allocation, but it will 1113 * fall back to that if necessary. 1114 */ 1115 if (!info->node_cache) 1116 new_leaf = kmalloc(sizeof(*new_leaf), GFP_KERNEL); 1117 1118 spin_lock(&info->lock); 1119 1120 if (!info->node_cache && new_leaf) { 1121 /* Save our speculative allocation into the cache */ 1122 INIT_LIST_HEAD(&new_leaf->msg_list); 1123 info->node_cache = new_leaf; 1124 info->qsize += sizeof(*new_leaf); 1125 } else { 1126 kfree(new_leaf); 1127 } 1128 1129 if (info->attr.mq_curmsgs == 0) { 1130 if (f.file->f_flags & O_NONBLOCK) { 1131 spin_unlock(&info->lock); 1132 ret = -EAGAIN; 1133 } else { 1134 wait.task = current; 1135 wait.state = STATE_NONE; 1136 ret = wq_sleep(info, RECV, timeout, &wait); 1137 msg_ptr = wait.msg; 1138 } 1139 } else { 1140 msg_ptr = msg_get(info); 1141 1142 inode->i_atime = inode->i_mtime = inode->i_ctime = 1143 CURRENT_TIME; 1144 1145 /* There is now free space in queue. */ 1146 pipelined_receive(info); 1147 spin_unlock(&info->lock); 1148 ret = 0; 1149 } 1150 if (ret == 0) { 1151 ret = msg_ptr->m_ts; 1152 1153 if ((u_msg_prio && put_user(msg_ptr->m_type, u_msg_prio)) || 1154 store_msg(u_msg_ptr, msg_ptr, msg_ptr->m_ts)) { 1155 ret = -EFAULT; 1156 } 1157 free_msg(msg_ptr); 1158 } 1159out_fput: 1160 fdput(f); 1161out: 1162 return ret; 1163} 1164 1165/* 1166 * Notes: the case when user wants us to deregister (with NULL as pointer) 1167 * and he isn't currently owner of notification, will be silently discarded. 1168 * It isn't explicitly defined in the POSIX. 1169 */ 1170SYSCALL_DEFINE2(mq_notify, mqd_t, mqdes, 1171 const struct sigevent __user *, u_notification) 1172{ 1173 int ret; 1174 struct fd f; 1175 struct sock *sock; 1176 struct inode *inode; 1177 struct sigevent notification; 1178 struct mqueue_inode_info *info; 1179 struct sk_buff *nc; 1180 1181 if (u_notification) { 1182 if (copy_from_user(¬ification, u_notification, 1183 sizeof(struct sigevent))) 1184 return -EFAULT; 1185 } 1186 1187 audit_mq_notify(mqdes, u_notification ? ¬ification : NULL); 1188 1189 nc = NULL; 1190 sock = NULL; 1191 if (u_notification != NULL) { 1192 if (unlikely(notification.sigev_notify != SIGEV_NONE && 1193 notification.sigev_notify != SIGEV_SIGNAL && 1194 notification.sigev_notify != SIGEV_THREAD)) 1195 return -EINVAL; 1196 if (notification.sigev_notify == SIGEV_SIGNAL && 1197 !valid_signal(notification.sigev_signo)) { 1198 return -EINVAL; 1199 } 1200 if (notification.sigev_notify == SIGEV_THREAD) { 1201 long timeo; 1202 1203 /* create the notify skb */ 1204 nc = alloc_skb(NOTIFY_COOKIE_LEN, GFP_KERNEL); 1205 if (!nc) { 1206 ret = -ENOMEM; 1207 goto out; 1208 } 1209 if (copy_from_user(nc->data, 1210 notification.sigev_value.sival_ptr, 1211 NOTIFY_COOKIE_LEN)) { 1212 ret = -EFAULT; 1213 goto out; 1214 } 1215 1216 /* TODO: add a header? */ 1217 skb_put(nc, NOTIFY_COOKIE_LEN); 1218 /* and attach it to the socket */ 1219retry: 1220 f = fdget(notification.sigev_signo); 1221 if (!f.file) { 1222 ret = -EBADF; 1223 goto out; 1224 } 1225 sock = netlink_getsockbyfilp(f.file); 1226 fdput(f); 1227 if (IS_ERR(sock)) { 1228 ret = PTR_ERR(sock); 1229 sock = NULL; 1230 goto out; 1231 } 1232 1233 timeo = MAX_SCHEDULE_TIMEOUT; 1234 ret = netlink_attachskb(sock, nc, &timeo, NULL); 1235 if (ret == 1) 1236 goto retry; 1237 if (ret) { 1238 sock = NULL; 1239 nc = NULL; 1240 goto out; 1241 } 1242 } 1243 } 1244 1245 f = fdget(mqdes); 1246 if (!f.file) { 1247 ret = -EBADF; 1248 goto out; 1249 } 1250 1251 inode = f.file->f_path.dentry->d_inode; 1252 if (unlikely(f.file->f_op != &mqueue_file_operations)) { 1253 ret = -EBADF; 1254 goto out_fput; 1255 } 1256 info = MQUEUE_I(inode); 1257 1258 ret = 0; 1259 spin_lock(&info->lock); 1260 if (u_notification == NULL) { 1261 if (info->notify_owner == task_tgid(current)) { 1262 remove_notification(info); 1263 inode->i_atime = inode->i_ctime = CURRENT_TIME; 1264 } 1265 } else if (info->notify_owner != NULL) { 1266 ret = -EBUSY; 1267 } else { 1268 switch (notification.sigev_notify) { 1269 case SIGEV_NONE: 1270 info->notify.sigev_notify = SIGEV_NONE; 1271 break; 1272 case SIGEV_THREAD: 1273 info->notify_sock = sock; 1274 info->notify_cookie = nc; 1275 sock = NULL; 1276 nc = NULL; 1277 info->notify.sigev_notify = SIGEV_THREAD; 1278 break; 1279 case SIGEV_SIGNAL: 1280 info->notify.sigev_signo = notification.sigev_signo; 1281 info->notify.sigev_value = notification.sigev_value; 1282 info->notify.sigev_notify = SIGEV_SIGNAL; 1283 break; 1284 } 1285 1286 info->notify_owner = get_pid(task_tgid(current)); 1287 info->notify_user_ns = get_user_ns(current_user_ns()); 1288 inode->i_atime = inode->i_ctime = CURRENT_TIME; 1289 } 1290 spin_unlock(&info->lock); 1291out_fput: 1292 fdput(f); 1293out: 1294 if (sock) { 1295 netlink_detachskb(sock, nc); 1296 } else if (nc) { 1297 dev_kfree_skb(nc); 1298 } 1299 return ret; 1300} 1301 1302SYSCALL_DEFINE3(mq_getsetattr, mqd_t, mqdes, 1303 const struct mq_attr __user *, u_mqstat, 1304 struct mq_attr __user *, u_omqstat) 1305{ 1306 int ret; 1307 struct mq_attr mqstat, omqstat; 1308 struct fd f; 1309 struct inode *inode; 1310 struct mqueue_inode_info *info; 1311 1312 if (u_mqstat != NULL) { 1313 if (copy_from_user(&mqstat, u_mqstat, sizeof(struct mq_attr))) 1314 return -EFAULT; 1315 if (mqstat.mq_flags & (~O_NONBLOCK)) 1316 return -EINVAL; 1317 } 1318 1319 f = fdget(mqdes); 1320 if (!f.file) { 1321 ret = -EBADF; 1322 goto out; 1323 } 1324 1325 inode = f.file->f_path.dentry->d_inode; 1326 if (unlikely(f.file->f_op != &mqueue_file_operations)) { 1327 ret = -EBADF; 1328 goto out_fput; 1329 } 1330 info = MQUEUE_I(inode); 1331 1332 spin_lock(&info->lock); 1333 1334 omqstat = info->attr; 1335 omqstat.mq_flags = f.file->f_flags & O_NONBLOCK; 1336 if (u_mqstat) { 1337 audit_mq_getsetattr(mqdes, &mqstat); 1338 spin_lock(&f.file->f_lock); 1339 if (mqstat.mq_flags & O_NONBLOCK) 1340 f.file->f_flags |= O_NONBLOCK; 1341 else 1342 f.file->f_flags &= ~O_NONBLOCK; 1343 spin_unlock(&f.file->f_lock); 1344 1345 inode->i_atime = inode->i_ctime = CURRENT_TIME; 1346 } 1347 1348 spin_unlock(&info->lock); 1349 1350 ret = 0; 1351 if (u_omqstat != NULL && copy_to_user(u_omqstat, &omqstat, 1352 sizeof(struct mq_attr))) 1353 ret = -EFAULT; 1354 1355out_fput: 1356 fdput(f); 1357out: 1358 return ret; 1359} 1360 1361static const struct inode_operations mqueue_dir_inode_operations = { 1362 .lookup = simple_lookup, 1363 .create = mqueue_create, 1364 .unlink = mqueue_unlink, 1365}; 1366 1367static const struct file_operations mqueue_file_operations = { 1368 .flush = mqueue_flush_file, 1369 .poll = mqueue_poll_file, 1370 .read = mqueue_read_file, 1371 .llseek = default_llseek, 1372}; 1373 1374static const struct super_operations mqueue_super_ops = { 1375 .alloc_inode = mqueue_alloc_inode, 1376 .destroy_inode = mqueue_destroy_inode, 1377 .evict_inode = mqueue_evict_inode, 1378 .statfs = simple_statfs, 1379}; 1380 1381static struct file_system_type mqueue_fs_type = { 1382 .name = "mqueue", 1383 .mount = mqueue_mount, 1384 .kill_sb = kill_litter_super, 1385}; 1386 1387int mq_init_ns(struct ipc_namespace *ns) 1388{ 1389 ns->mq_queues_count = 0; 1390 ns->mq_queues_max = DFLT_QUEUESMAX; 1391 ns->mq_msg_max = DFLT_MSGMAX; 1392 ns->mq_msgsize_max = DFLT_MSGSIZEMAX; 1393 ns->mq_msg_default = DFLT_MSG; 1394 ns->mq_msgsize_default = DFLT_MSGSIZE; 1395 1396 ns->mq_mnt = kern_mount_data(&mqueue_fs_type, ns); 1397 if (IS_ERR(ns->mq_mnt)) { 1398 int err = PTR_ERR(ns->mq_mnt); 1399 ns->mq_mnt = NULL; 1400 return err; 1401 } 1402 return 0; 1403} 1404 1405void mq_clear_sbinfo(struct ipc_namespace *ns) 1406{ 1407 ns->mq_mnt->mnt_sb->s_fs_info = NULL; 1408} 1409 1410void mq_put_mnt(struct ipc_namespace *ns) 1411{ 1412 kern_unmount(ns->mq_mnt); 1413} 1414 1415static int __init init_mqueue_fs(void) 1416{ 1417 int error; 1418 1419 mqueue_inode_cachep = kmem_cache_create("mqueue_inode_cache", 1420 sizeof(struct mqueue_inode_info), 0, 1421 SLAB_HWCACHE_ALIGN, init_once); 1422 if (mqueue_inode_cachep == NULL) 1423 return -ENOMEM; 1424 1425 /* ignore failures - they are not fatal */ 1426 mq_sysctl_table = mq_register_sysctl_table(); 1427 1428 error = register_filesystem(&mqueue_fs_type); 1429 if (error) 1430 goto out_sysctl; 1431 1432 spin_lock_init(&mq_lock); 1433 1434 error = mq_init_ns(&init_ipc_ns); 1435 if (error) 1436 goto out_filesystem; 1437 1438 return 0; 1439 1440out_filesystem: 1441 unregister_filesystem(&mqueue_fs_type); 1442out_sysctl: 1443 if (mq_sysctl_table) 1444 unregister_sysctl_table(mq_sysctl_table); 1445 kmem_cache_destroy(mqueue_inode_cachep); 1446 return error; 1447} 1448 1449__initcall(init_mqueue_fs); 1450